To add to the above, which in my experience is correct:

1. Comping may not include the next full year. It depends on the airline and on when in the year you get comped. (I was comped to AA Platinum on the basis of DL Gold Medallion in April 1998 and told I would have to requalify that year. It was OK with me based on known travel plans for the next eight months.) Check your specific situation if you have concerns about being able to requalify in what remains of the current year.

2. Airlines will generally not comp their top (typically 100,000-mile or comparable) level, no matter what status you have with another one. Second-tier is the best one can normally do, though there are exceptions to everything.